Abstract: Tuberculosis kills 2 million people every year. The increasing prevalence of multiple drug- resistant (MDR) infections and the emergence of extensively/completely drug-resistant (XDR/CDR) tubercle bacilli are making currently chemotherapies less and less effective. The long-term goal of this proposal is to develop a novel therapy for tuberculosis based on our recent observation that anaerobic shock causes rapid and extensive cell lysis of Mycobacterium tuberculosis (e.g. >105 drop in bacterial survival within 5 min). Two general directions will be explored. One is treatment of lungs of infected hosts with anaerobic gas. Initially, rabbits infected with M. tuberculosis, including MDR and XDR clinical isolates, will be used to test the efficacy and safety of anaerobic gas mixtures optimized in vitro. Clinical trials, for which additional funding will be sought, will be designed based on our rabbit work. Our overall achievement of this line of work should provide a medical procedure that will achieve a positive to negative sputum bacilli conversion in hours, or perhaps even minutes, rather than the weeks required for traditional combination chemotherapy. The second direction focuses on the molecular mechanisms underlying anaerobic shock-mediated rapid cell lysis. Genetic, genomic, and biochemical approaches will be used to identify relevant genes and the encoded proteins involved in anaerobic shock-induced cell lysis using straight-forward turbidity and fluorescence assays. An in vivo cyclic peptide library will also be constructed and screened for autolysis- inducing activities similar to that conferred by anaerobic shock. Information gained from this second part of the work will be used to design high throughput screens for small-molecule activators of mycobacterial cell lysis. The success of this project will revolutionize tuberculosis therapy and generate a novel drug that would rapidly cure tuberculosis regardless of its drug- resistance profile (MDR or XDR) or physiological status (growing or dormant). Public Health Relevance: Tuberculosis infects a third of the world's population and kills 2 million people a year. The increasing problem of drug resistance may soon make all currently available treatment options ineffective. The present program seeks to develop a novel, rapid, and highly efficient treatment of tuberculosis upon induction of self-destructive autolysis of Mycobacterium tuberculosis.